Which one has largest number of isomers ?

Options

A. `[Co(en)_(2)Cl_(2)]^(+)`
B. `[Co(NH_(3))_(5)Cl]^(2+)`
C. `[Ir(PhR_(3))_(2)H(CO)]^(2+)`
D. `[Ru(NH_(3))_(4)Cl_(2)]^(+)`

Answer

A

Explanation

(a) `[M(A A)_(2)Cl_(2)] cis to 2, trans to 1, Total=3`